From 73f086bdea4cd64ba6cc498b47c204233ddf3c38 Mon Sep 17 00:00:00 2001
From: Adam Cozzette <adamc@aspect.build>
Date: Wed, 3 Jun 2026 09:55:13 -0700
Subject: [PATCH 01/10] feat: add $(rlocation ...) syntax as a cleaner
 alternative to $$RUNFILES_DIR/$(rlocationpath ...)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 examples/rspack/BUILD.bazel              |  2 +-
 examples/vite3/BUILD.bazel               |  2 +-
 examples/vite6/BUILD.bazel               |  2 +-
 examples/webpack_cli/BUILD.bazel         |  2 +-
 js/private/coverage/bundle/BUILD.bazel   |  2 +-
 js/private/devserver/src/BUILD.bazel     |  2 +-
 js/private/js_binary.bzl                 | 39 +++++++++++++++++++++---
 js/private/test/node-patches/BUILD.bazel |  2 +-
 js/private/worker/src/BUILD.bazel        |  2 +-
 npm/private/lifecycle/src/BUILD.bazel    |  2 +-
 10 files changed, 43 insertions(+), 14 deletions(-)

diff --git a/examples/rspack/BUILD.bazel b/examples/rspack/BUILD.bazel
index e61fe6c7e..79f307fd8 100644
--- a/examples/rspack/BUILD.bazel
+++ b/examples/rspack/BUILD.bazel
@@ -27,7 +27,7 @@ bin.rspack(
     fixed_args = [
         "build",
         "--config",
-        "$$RUNFILES_DIR/$(rlocationpath :rspack_config)",
+        "$(rlocation :rspack_config)",
     ],
     use_execroot_entry_point = False,
 )
diff --git a/examples/vite3/BUILD.bazel b/examples/vite3/BUILD.bazel
index 8503520ab..2d632b67b 100644
--- a/examples/vite3/BUILD.bazel
+++ b/examples/vite3/BUILD.bazel
@@ -30,7 +30,7 @@ vite_bin.vite(
     fixed_args = [
         "build",
         "--config",
-        "$$RUNFILES_DIR/$(rlocationpath :vite-config)",
+        "$(rlocation :vite-config)",
     ],
     out_dirs = ["build"],
 )
diff --git a/examples/vite6/BUILD.bazel b/examples/vite6/BUILD.bazel
index 86f48bfb5..0b649dc6f 100644
--- a/examples/vite6/BUILD.bazel
+++ b/examples/vite6/BUILD.bazel
@@ -30,7 +30,7 @@ vite_bin.vite(
     fixed_args = [
         "build",
         "--config",
-        "$$RUNFILES_DIR/$(rlocationpath :vite-config)",
+        "$(rlocation :vite-config)",
     ],
     out_dirs = ["build"],
 )
diff --git a/examples/webpack_cli/BUILD.bazel b/examples/webpack_cli/BUILD.bazel
index 733d8d93e..5f9e744c9 100644
--- a/examples/webpack_cli/BUILD.bazel
+++ b/examples/webpack_cli/BUILD.bazel
@@ -35,7 +35,7 @@ bin.webpack_cli(
     data = [":webpack-config"],
     fixed_args = [
         "--config",
-        "$$RUNFILES_DIR/$(rlocationpath :webpack-config)",
+        "$(rlocation :webpack-config)",
     ],
     log_level = "debug",
 )
diff --git a/js/private/coverage/bundle/BUILD.bazel b/js/private/coverage/bundle/BUILD.bazel
index 34ce8bb5f..7eafe931f 100644
--- a/js/private/coverage/bundle/BUILD.bazel
+++ b/js/private/coverage/bundle/BUILD.bazel
@@ -27,7 +27,7 @@ rollup_bin.rollup(
     fixed_args = [
         "c8.js",
         "--config",
-        "$$RUNFILES_DIR/$(rlocationpath :config)",
+        "$(rlocation :config)",
         "--format",
         "cjs",
         "--file",
diff --git a/js/private/devserver/src/BUILD.bazel b/js/private/devserver/src/BUILD.bazel
index a8ae232f1..27d48a5bc 100644
--- a/js/private/devserver/src/BUILD.bazel
+++ b/js/private/devserver/src/BUILD.bazel
@@ -22,7 +22,7 @@ rollup_bin.rollup(
     fixed_args = [
         "js_run_devserver.mjs",
         "--config",
-        "$$RUNFILES_DIR/$(rlocationpath :config)",
+        "$(rlocation :config)",
         "--format",
         "es",
         "--file",
diff --git a/js/private/js_binary.bzl b/js/private/js_binary.bzl
index 3e864f8fd..2ce059be7 100644
--- a/js/private/js_binary.bzl
+++ b/js/private/js_binary.bzl
@@ -72,20 +72,23 @@ _ATTRS = {
     "env": attr.string_dict(
         doc = """Environment variables of the action.
 
-        Subject to [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
+        Subject to `$(rlocation ...)`,
+        [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
         and ["Make variable"](https://bazel.build/reference/be/make-variables) substitution if `expand_env` is set to True.
         """,
     ),
     "expand_args": attr.bool(
         default = True,
-        doc = """Enables [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
+        doc = """Enables `$(rlocation ...)`,
+        [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
         and ["Make variable"](https://bazel.build/reference/be/make-variables) substitution for `fixed_args`.
 
         This comes at some analysis-time cost even for a set of args that does not have any expansions.""",
     ),
     "expand_env": attr.bool(
         default = True,
-        doc = """Enables [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
+        doc = """Enables `$(rlocation ...)`,
+        [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
         and ["Make variable"](https://bazel.build/reference/be/make-variables) substitution for `env`.
 
         This comes at some analysis-time cost even for a set of envs that does not have any expansions.""",
@@ -94,7 +97,8 @@ _ATTRS = {
         doc = """Fixed command line arguments to pass to the Node.js when this
         binary target is executed.
 
-        Subject to [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
+        Subject to `$(rlocation ...)`,
+        [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
         and ["Make variable"](https://bazel.build/reference/be/make-variables) substitution if `expand_args` is set to True.
 
         Unlike the built-in `args`, which are only passed to the target when it is
@@ -275,8 +279,33 @@ _ENV_SET = """export {var}={quoted_value}"""
 _ENV_SET_IFF_NOT_SET = """if [[ -z "${{{var}:-}}" ]]; then export {var}={quoted_value}; fi"""
 _NODE_OPTION = """JS_BINARY__NODE_OPTIONS+=(\"{value}\")"""
 
+def _expand_rlocation_refs(value):
+    """Pre-processes $(rlocation <label>) into $$RUNFILES_DIR/$(rlocationpath <label>).
+
+    After this transformation, the standard expand_locations/expand_variables chain
+    resolves the rlocationpath and converts $$ to a literal $.
+    """
+    result = []
+    remaining = value
+    prefix = "$(rlocation "
+    for _ in range(len(value)):
+        idx = remaining.find(prefix)
+        if idx == -1:
+            break
+        result.append(remaining[:idx])
+        remaining = remaining[idx + len(prefix):]
+        end = remaining.find(")")
+        if end == -1:
+            fail("Unclosed $(rlocation ...) in: " + value)
+        label_str = remaining[:end]
+        result.append("$$RUNFILES_DIR/$(rlocationpath " + label_str + ")")
+        remaining = remaining[end + 1:]
+    result.append(remaining)
+    return "".join(result)
+
 def _expand_env_if_needed(ctx, value):
     if ctx.attr.expand_env:
+        value = _expand_rlocation_refs(value)
         return " ".join([expand_variables(ctx, exp, attribute_name = "env") for exp in expand_locations(ctx, value, ctx.attr.data).split(" ")])
     return value
 
@@ -374,7 +403,7 @@ def _bash_launcher(ctx, nodeinfo, entry_point_path, log_prefix_rule_set, log_pre
         node_options.append(_NODE_OPTION.format(value = "--preserve-symlinks-main"))
 
     if ctx.attr.expand_args:
-        fixed_args = [expand_variables(ctx, expand_locations(ctx, fixed_arg, ctx.attr.data)) for fixed_arg in fixed_args]
+        fixed_args = [expand_variables(ctx, expand_locations(ctx, _expand_rlocation_refs(fixed_arg), ctx.attr.data)) for fixed_arg in fixed_args]
 
     toolchain_files = []
     if is_windows:
diff --git a/js/private/test/node-patches/BUILD.bazel b/js/private/test/node-patches/BUILD.bazel
index 902b18277..d1baa2966 100644
--- a/js/private/test/node-patches/BUILD.bazel
+++ b/js/private/test/node-patches/BUILD.bazel
@@ -69,7 +69,7 @@ babel_bin.babel(
     data = [":babel_config"],
     fixed_args = [
         "--config-file",
-        "$$RUNFILES_DIR/$(rlocationpath :babel_config)",
+        "$(rlocation :babel_config)",
         "--extensions",
         ".mjs",
         "--out-file-extension",
diff --git a/js/private/worker/src/BUILD.bazel b/js/private/worker/src/BUILD.bazel
index d439aeb58..d64c71b14 100644
--- a/js/private/worker/src/BUILD.bazel
+++ b/js/private/worker/src/BUILD.bazel
@@ -32,7 +32,7 @@ rollup_bin.rollup(
     fixed_args = [
         "index.ts",
         "--config",
-        "$$RUNFILES_DIR/$(rlocationpath :config)",
+        "$(rlocation :config)",
         "--format",
         "cjs",
         "--file",
diff --git a/npm/private/lifecycle/src/BUILD.bazel b/npm/private/lifecycle/src/BUILD.bazel
index 84c6d4b3f..6d6be64c2 100644
--- a/npm/private/lifecycle/src/BUILD.bazel
+++ b/npm/private/lifecycle/src/BUILD.bazel
@@ -26,7 +26,7 @@ rollup_bin.rollup(
     fixed_args = [
         "lifecycle-hooks.js",
         "--config",
-        "$$RUNFILES_DIR/$(rlocationpath //npm/private/lifecycle:rollup_config)",
+        "$(rlocation //npm/private/lifecycle:rollup_config)",
         "--format",
         "cjs",
         "--file",

From baeb9ab87772c010ee1924edeed3ba54429b871f Mon Sep 17 00:00:00 2001
From: Adam Cozzette <adamc@aspect.build>
Date: Wed, 3 Jun 2026 10:43:06 -0700
Subject: [PATCH 02/10] Update documentation

---
 docs/use_execroot_entry_point.md | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/docs/use_execroot_entry_point.md b/docs/use_execroot_entry_point.md
index 84f8bf3d4..3794911c4 100644
--- a/docs/use_execroot_entry_point.md
+++ b/docs/use_execroot_entry_point.md
@@ -104,7 +104,7 @@ bin.rspack(
     fixed_args = [
         "build",
         "--config",
-        "$$RUNFILES_DIR/$(rlocationpath :rspack_config)",
+        "$(rlocation :rspack_config)",
     ],
     use_execroot_entry_point = False,
 )
@@ -128,10 +128,7 @@ Key points:
   `__dirname`, for specifying the output path. This is key, because the config
   file (and therefore `__dirname`) will be in the runfiles directory and not
   the output tree.
-- We refer to `"$$RUNFILES_DIR/$(rlocationpath :rspack_config)"` in
-  `fixed_args`. `$(rlocationpath ...)` is evaluated at analysis time and
-  determines the path to the config file within the runfiles directory. This
-  argument must go in `fixed_args` rather than `args`, to allow `$RUNFILES_DIR`
-  to be evaluated at run time. Note the double dollar sign (`$$`) to prevent
-  the `js_binary` implementation from attempting to evaluate that variable at
-  analysis time.
+- We refer to `"$(rlocation :rspack_config)"` in `fixed_args`. The `js_binary`
+  implementation expands this to the absolute path to the config file in the
+  runfiles directory. Note that this must go in `fixed_args` rather than
+  `args`.

From a440d5b291cd55821c3dac32abd2af16ff7e551b Mon Sep 17 00:00:00 2001
From: Adam Cozzette <adamc@aspect.build>
Date: Wed, 3 Jun 2026 10:47:20 -0700
Subject: [PATCH 03/10] fix: restrict $(rlocation ...) expansion to fixed_args
 only

env values are quoted and stored as literal strings, so $RUNFILES_DIR
would not be evaluated at runtime.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 js/private/js_binary.bzl | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/js/private/js_binary.bzl b/js/private/js_binary.bzl
index 2ce059be7..7fb5dfa00 100644
--- a/js/private/js_binary.bzl
+++ b/js/private/js_binary.bzl
@@ -72,8 +72,7 @@ _ATTRS = {
     "env": attr.string_dict(
         doc = """Environment variables of the action.
 
-        Subject to `$(rlocation ...)`,
-        [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
+        Subject to [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
         and ["Make variable"](https://bazel.build/reference/be/make-variables) substitution if `expand_env` is set to True.
         """,
     ),
@@ -87,8 +86,7 @@ _ATTRS = {
     ),
     "expand_env": attr.bool(
         default = True,
-        doc = """Enables `$(rlocation ...)`,
-        [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
+        doc = """Enables [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
         and ["Make variable"](https://bazel.build/reference/be/make-variables) substitution for `env`.
 
         This comes at some analysis-time cost even for a set of envs that does not have any expansions.""",
@@ -305,7 +303,6 @@ def _expand_rlocation_refs(value):
 
 def _expand_env_if_needed(ctx, value):
     if ctx.attr.expand_env:
-        value = _expand_rlocation_refs(value)
         return " ".join([expand_variables(ctx, exp, attribute_name = "env") for exp in expand_locations(ctx, value, ctx.attr.data).split(" ")])
     return value
 

From 6b9afccacd472a05ae2923df24a9a07fd5f48bba Mon Sep 17 00:00:00 2001
From: Adam Cozzette <adamc@aspect.build>
Date: Wed, 3 Jun 2026 11:05:51 -0700
Subject: [PATCH 04/10] Update docstring

---
 js/private/js_binary.bzl | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/js/private/js_binary.bzl b/js/private/js_binary.bzl
index 7fb5dfa00..79ab0f13a 100644
--- a/js/private/js_binary.bzl
+++ b/js/private/js_binary.bzl
@@ -78,9 +78,9 @@ _ATTRS = {
     ),
     "expand_args": attr.bool(
         default = True,
-        doc = """Enables `$(rlocation ...)`,
-        [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
-        and ["Make variable"](https://bazel.build/reference/be/make-variables) substitution for `fixed_args`.
+        doc = """Enables [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables),
+        ["Make variable"](https://bazel.build/reference/be/make-variables), and our own custom `$(rlocation)`
+        substitution for `fixed_args`.
 
         This comes at some analysis-time cost even for a set of args that does not have any expansions.""",
     ),
@@ -95,9 +95,14 @@ _ATTRS = {
         doc = """Fixed command line arguments to pass to the Node.js when this
         binary target is executed.
 
-        Subject to `$(rlocation ...)`,
-        [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables)
-        and ["Make variable"](https://bazel.build/reference/be/make-variables) substitution if `expand_args` is set to True.
+        Subject to [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables),
+        ["Make variable"](https://bazel.build/reference/be/make-variables), and `$(rlocation)` substitution
+        if `expand_args` is set to True.
+
+        The `$(rlocation :label)` syntax is unique to `js_binary` and expands to the
+        absolute path to `:label` in the runfiles. This is supported only in `fixed_args`,
+        because part of the evaluation has to occur at run time, inside the wrapper
+        script.
 
         Unlike the built-in `args`, which are only passed to the target when it is
         executed either by the `bazel run` command or as a test, `fixed_args` are baked

From 54da0de731c677f1af1176b5865e220b5643c982 Mon Sep 17 00:00:00 2001
From: Adam Cozzette <adamc@aspect.build>
Date: Wed, 3 Jun 2026 11:12:58 -0700
Subject: [PATCH 05/10] refactor: move expand_rlocation_refs to js_helpers and
 expose via js_lib_helpers

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 js/libs.bzl               |  2 ++
 js/private/js_binary.bzl  | 28 ++--------------------------
 js/private/js_helpers.bzl | 24 ++++++++++++++++++++++++
 3 files changed, 28 insertions(+), 26 deletions(-)

diff --git a/js/libs.bzl b/js/libs.bzl
index abd332b21..e9e1ca6d1 100644
--- a/js/libs.bzl
+++ b/js/libs.bzl
@@ -8,6 +8,7 @@ load(
     "//js/private:js_helpers.bzl",
     _LOG_LEVELS = "LOG_LEVELS",
     _envs_for_log_level = "envs_for_log_level",
+    _expand_rlocation_refs = "expand_rlocation_refs",
     _gather_files_from_js_infos = "gather_files_from_js_infos",
     _gather_npm_package_store_infos = "gather_npm_package_store_infos",
     _gather_npm_sources = "gather_npm_sources",
@@ -25,6 +26,7 @@ js_library_lib = _js_library_lib
 
 js_lib_helpers = struct(
     envs_for_log_level = _envs_for_log_level,
+    expand_rlocation_refs = _expand_rlocation_refs,
     gather_files_from_js_infos = _gather_files_from_js_infos,
     gather_npm_sources = _gather_npm_sources,
     gather_npm_package_store_infos = _gather_npm_package_store_infos,
diff --git a/js/private/js_binary.bzl b/js/private/js_binary.bzl
index 79ab0f13a..7a85ec33a 100644
--- a/js/private/js_binary.bzl
+++ b/js/private/js_binary.bzl
@@ -5,7 +5,7 @@ load("@bazel_lib//lib:directory_path.bzl", "DirectoryPathInfo")
 load("@bazel_lib//lib:expand_make_vars.bzl", "expand_locations", "expand_variables")
 load("@bazel_lib//lib:windows_utils.bzl", "create_windows_native_launcher_script")
 load(":bash.bzl", "BASH_INITIALIZE_RUNFILES")
-load(":js_helpers.bzl", "LOG_LEVELS", "envs_for_log_level", "gather_files_from_js_infos", "gather_runfiles")
+load(":js_helpers.bzl", "LOG_LEVELS", "envs_for_log_level", "expand_rlocation_refs", "gather_files_from_js_infos", "gather_runfiles")
 
 _ATTRS = {
     "chdir": attr.string(
@@ -282,30 +282,6 @@ _ENV_SET = """export {var}={quoted_value}"""
 _ENV_SET_IFF_NOT_SET = """if [[ -z "${{{var}:-}}" ]]; then export {var}={quoted_value}; fi"""
 _NODE_OPTION = """JS_BINARY__NODE_OPTIONS+=(\"{value}\")"""
 
-def _expand_rlocation_refs(value):
-    """Pre-processes $(rlocation <label>) into $$RUNFILES_DIR/$(rlocationpath <label>).
-
-    After this transformation, the standard expand_locations/expand_variables chain
-    resolves the rlocationpath and converts $$ to a literal $.
-    """
-    result = []
-    remaining = value
-    prefix = "$(rlocation "
-    for _ in range(len(value)):
-        idx = remaining.find(prefix)
-        if idx == -1:
-            break
-        result.append(remaining[:idx])
-        remaining = remaining[idx + len(prefix):]
-        end = remaining.find(")")
-        if end == -1:
-            fail("Unclosed $(rlocation ...) in: " + value)
-        label_str = remaining[:end]
-        result.append("$$RUNFILES_DIR/$(rlocationpath " + label_str + ")")
-        remaining = remaining[end + 1:]
-    result.append(remaining)
-    return "".join(result)
-
 def _expand_env_if_needed(ctx, value):
     if ctx.attr.expand_env:
         return " ".join([expand_variables(ctx, exp, attribute_name = "env") for exp in expand_locations(ctx, value, ctx.attr.data).split(" ")])
@@ -405,7 +381,7 @@ def _bash_launcher(ctx, nodeinfo, entry_point_path, log_prefix_rule_set, log_pre
         node_options.append(_NODE_OPTION.format(value = "--preserve-symlinks-main"))
 
     if ctx.attr.expand_args:
-        fixed_args = [expand_variables(ctx, expand_locations(ctx, _expand_rlocation_refs(fixed_arg), ctx.attr.data)) for fixed_arg in fixed_args]
+        fixed_args = [expand_variables(ctx, expand_locations(ctx, expand_rlocation_refs(fixed_arg), ctx.attr.data)) for fixed_arg in fixed_args]
 
     toolchain_files = []
     if is_windows:
diff --git a/js/private/js_helpers.bzl b/js/private/js_helpers.bzl
index 3613839b8..d4dc5303b 100644
--- a/js/private/js_helpers.bzl
+++ b/js/private/js_helpers.bzl
@@ -190,6 +190,30 @@ def gather_runfiles(
         for target in deps
     ])
 
+def expand_rlocation_refs(value):
+    """Pre-processes $(rlocation <label>) into $$RUNFILES_DIR/$(rlocationpath <label>).
+
+    After this transformation, the standard expand_locations/expand_variables chain
+    resolves the rlocationpath and converts $$ to a literal $.
+    """
+    result = []
+    remaining = value
+    prefix = "$(rlocation "
+    for _ in range(len(value)):
+        idx = remaining.find(prefix)
+        if idx == -1:
+            break
+        result.append(remaining[:idx])
+        remaining = remaining[idx + len(prefix):]
+        end = remaining.find(")")
+        if end == -1:
+            fail("Unclosed $(rlocation ...) in: " + value)
+        label_str = remaining[:end]
+        result.append("$$RUNFILES_DIR/$(rlocationpath " + label_str + ")")
+        remaining = remaining[end + 1:]
+    result.append(remaining)
+    return "".join(result)
+
 LOG_LEVELS = {
     "fatal": 1,
     "error": 2,

From 45d2cbb425386aaaeefd8f62f4c792b0b7944118 Mon Sep 17 00:00:00 2001
From: Adam Cozzette <adamc@aspect.build>
Date: Wed, 3 Jun 2026 14:08:14 -0700
Subject: [PATCH 06/10] test: add unit tests for expand_rlocation_refs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 js/private/test/BUILD.bazel         |  3 ++
 js/private/test/js_helpers_test.bzl | 61 +++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)
 create mode 100644 js/private/test/js_helpers_test.bzl

diff --git a/js/private/test/BUILD.bazel b/js/private/test/BUILD.bazel
index 7e05f6aac..80778e4f7 100644
--- a/js/private/test/BUILD.bazel
+++ b/js/private/test/BUILD.bazel
@@ -2,6 +2,7 @@ load("@bazel_lib//lib:write_source_files.bzl", "write_source_files")
 load("@bazel_lib_host//:defs.bzl", "host")
 load("@bazel_skylib//rules:write_file.bzl", "write_file")
 load("//js:defs.bzl", "js_binary", "js_library", "js_test")
+load(":js_helpers_test.bzl", "js_helpers_test_suite")
 load(":js_library_test.bzl", "js_library_test_suite")
 load(":run_environment_info_test.bzl", "run_environment_info_test_suite")
 
@@ -39,6 +40,8 @@ write_source_files(
     },
 )
 
+js_helpers_test_suite(name = "js_helpers_test")
+
 js_library_test_suite(name = "js_library_test")
 
 run_environment_info_test_suite(name = "run_environment_info_tests")
diff --git a/js/private/test/js_helpers_test.bzl b/js/private/test/js_helpers_test.bzl
new file mode 100644
index 000000000..2409d0631
--- /dev/null
+++ b/js/private/test/js_helpers_test.bzl
@@ -0,0 +1,61 @@
+"""Tests for js_helpers utility functions"""
+
+load("@bazel_skylib//lib:unittest.bzl", "asserts", "unittest")
+load("//js/private:js_helpers.bzl", "expand_rlocation_refs")
+
+def _no_rlocation_refs_test(ctx):
+    env = unittest.begin(ctx)
+    asserts.equals(env, "build --config myconfig.json", expand_rlocation_refs("build --config myconfig.json"))
+    return unittest.end(env)
+
+def _single_rlocation_ref_test(ctx):
+    env = unittest.begin(ctx)
+    asserts.equals(
+        env,
+        "$$RUNFILES_DIR/$(rlocationpath :rspack_config)",
+        expand_rlocation_refs("$(rlocation :rspack_config)"),
+    )
+    return unittest.end(env)
+
+def _rlocation_ref_with_surrounding_text_test(ctx):
+    env = unittest.begin(ctx)
+    asserts.equals(
+        env,
+        "--config $$RUNFILES_DIR/$(rlocationpath :my_config) --output out.js",
+        expand_rlocation_refs("--config $(rlocation :my_config) --output out.js"),
+    )
+    return unittest.end(env)
+
+def _multiple_rlocation_refs_test(ctx):
+    env = unittest.begin(ctx)
+    asserts.equals(
+        env,
+        "$$RUNFILES_DIR/$(rlocationpath :foo) $$RUNFILES_DIR/$(rlocationpath :bar)",
+        expand_rlocation_refs("$(rlocation :foo) $(rlocation :bar)"),
+    )
+    return unittest.end(env)
+
+def _absolute_label_rlocation_ref_test(ctx):
+    env = unittest.begin(ctx)
+    asserts.equals(
+        env,
+        "$$RUNFILES_DIR/$(rlocationpath //some/pkg:target)",
+        expand_rlocation_refs("$(rlocation //some/pkg:target)"),
+    )
+    return unittest.end(env)
+
+no_rlocation_refs_test = unittest.make(_no_rlocation_refs_test)
+single_rlocation_ref_test = unittest.make(_single_rlocation_ref_test)
+rlocation_ref_with_surrounding_text_test = unittest.make(_rlocation_ref_with_surrounding_text_test)
+multiple_rlocation_refs_test = unittest.make(_multiple_rlocation_refs_test)
+absolute_label_rlocation_ref_test = unittest.make(_absolute_label_rlocation_ref_test)
+
+def js_helpers_test_suite(name):
+    unittest.suite(
+        name,
+        no_rlocation_refs_test,
+        single_rlocation_ref_test,
+        rlocation_ref_with_surrounding_text_test,
+        multiple_rlocation_refs_test,
+        absolute_label_rlocation_ref_test,
+    )

From 2aed59f1f50a0ee134ec17251cb0abb93d1dc08e Mon Sep 17 00:00:00 2001
From: Adam Cozzette <adamc@aspect.build>
Date: Wed, 3 Jun 2026 14:19:27 -0700
Subject: [PATCH 07/10] test: fix misleading multi-word string in
 no_rlocation_refs test

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 js/private/test/js_helpers_test.bzl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/js/private/test/js_helpers_test.bzl b/js/private/test/js_helpers_test.bzl
index 2409d0631..4d8ed7d04 100644
--- a/js/private/test/js_helpers_test.bzl
+++ b/js/private/test/js_helpers_test.bzl
@@ -5,7 +5,7 @@ load("//js/private:js_helpers.bzl", "expand_rlocation_refs")
 
 def _no_rlocation_refs_test(ctx):
     env = unittest.begin(ctx)
-    asserts.equals(env, "build --config myconfig.json", expand_rlocation_refs("build --config myconfig.json"))
+    asserts.equals(env, "build", expand_rlocation_refs("build"))
     return unittest.end(env)
 
 def _single_rlocation_ref_test(ctx):

From c8bcba6317b44a42d09a09dfbc6d24609fb38ebe Mon Sep 17 00:00:00 2001
From: Adam Cozzette <adamc@aspect.build>
Date: Wed, 3 Jun 2026 14:21:16 -0700
Subject: [PATCH 08/10] test: use single-argument style in
 expand_rlocation_refs tests

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 js/private/test/js_helpers_test.bzl | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/js/private/test/js_helpers_test.bzl b/js/private/test/js_helpers_test.bzl
index 4d8ed7d04..ade38507d 100644
--- a/js/private/test/js_helpers_test.bzl
+++ b/js/private/test/js_helpers_test.bzl
@@ -21,8 +21,8 @@ def _rlocation_ref_with_surrounding_text_test(ctx):
     env = unittest.begin(ctx)
     asserts.equals(
         env,
-        "--config $$RUNFILES_DIR/$(rlocationpath :my_config) --output out.js",
-        expand_rlocation_refs("--config $(rlocation :my_config) --output out.js"),
+        "--config=$$RUNFILES_DIR/$(rlocationpath :my_config)",
+        expand_rlocation_refs("--config=$(rlocation :my_config)"),
     )
     return unittest.end(env)
 
@@ -30,8 +30,8 @@ def _multiple_rlocation_refs_test(ctx):
     env = unittest.begin(ctx)
     asserts.equals(
         env,
-        "$$RUNFILES_DIR/$(rlocationpath :foo) $$RUNFILES_DIR/$(rlocationpath :bar)",
-        expand_rlocation_refs("$(rlocation :foo) $(rlocation :bar)"),
+        "$$RUNFILES_DIR/$(rlocationpath :foo):$$RUNFILES_DIR/$(rlocationpath :bar)",
+        expand_rlocation_refs("$(rlocation :foo):$(rlocation :bar)"),
     )
     return unittest.end(env)
 

From bc0e9037b9c98ea55ea0c168a4cf73f0919308e5 Mon Sep 17 00:00:00 2001
From: Adam Cozzette <adamc@aspect.build>
Date: Thu, 4 Jun 2026 08:12:25 -0700
Subject: [PATCH 09/10] Add comment about closing parentheses in Bazel labels

---
 js/private/js_helpers.bzl | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/js/private/js_helpers.bzl b/js/private/js_helpers.bzl
index d4dc5303b..a7f6d180c 100644
--- a/js/private/js_helpers.bzl
+++ b/js/private/js_helpers.bzl
@@ -205,6 +205,11 @@ def expand_rlocation_refs(value):
             break
         result.append(remaining[:idx])
         remaining = remaining[idx + len(prefix):]
+        # Parentheses are allowed in Bazel target names and could therefore
+        # theoretically appear in a label. We just look for the first closing
+        # parenthesis without handling that possibility, as this is what Bazel
+        # itself does:
+        # https://github.com/bazelbuild/bazel/blob/b4f16d988ddebc1891d7af57622ec5aff149a838/src/main/java/com/google/devtools/build/lib/analysis/LocationExpander.java#L179
         end = remaining.find(")")
         if end == -1:
             fail("Unclosed $(rlocation ...) in: " + value)

From b84b6c66452715a140cbc375e5bb32613cad4f36 Mon Sep 17 00:00:00 2001
From: Adam Cozzette <adamc@aspect.build>
Date: Thu, 4 Jun 2026 08:17:48 -0700
Subject: [PATCH 10/10] buildifier

---
 js/private/js_helpers.bzl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/js/private/js_helpers.bzl b/js/private/js_helpers.bzl
index a7f6d180c..355e9aecf 100644
--- a/js/private/js_helpers.bzl
+++ b/js/private/js_helpers.bzl
@@ -205,6 +205,7 @@ def expand_rlocation_refs(value):
             break
         result.append(remaining[:idx])
         remaining = remaining[idx + len(prefix):]
+
         # Parentheses are allowed in Bazel target names and could therefore
         # theoretically appear in a label. We just look for the first closing
         # parenthesis without handling that possibility, as this is what Bazel